Combined fungicide and insecticide



Patented May 30, 1933 UNITED STATES,

PATENT OFFICE HARRY C..YOUNG, OF WOOSTER, OHIO, ASSIGN OR TO THE GRASSELLI (ZHIilIliIICAI: COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF DELAWARE 'comsman FUNGICIDE AND msnc'rrcnm No Drawing.

It has inlate years been shown that the .beneficial action of sulfur in fighting crypto'gamic diseases of plants is mainly, if not entirely due to the presence in minute amounts in the sulfur of oxidation products of the type of polythionic acids.

These oxidation products are not very stable, and their existence in sulfur dusts 1s often detrimentally affected by the presence of other substances in the dust. It is, for 1nstance, known that admixtures of lead or calcium arsenate to sulfur dusts very materlally affect the fungicidal properties of the dusts, and I believe that these arsenlcals either prevent formation of polythiomc acids or speed up their decompos1tion when formed.

I have found that the fungicidal properties of sulfur persists entirely in mixtures of sulfur and manganese arsenates, and my invention comprises novel compositions of matter having fungicidal and insecticidal properties, said compositions comprising mixtures of finely divided sulfur with finely divided manganese arsenate.

It is also known that the active polythionic acids form particularly under the conditions when sulfur dusts as applied as fungicides adhere to the plants, but that under these same conditions further oxidation or decomposition of the polythionic acids takes place, which may explain the irregularities sometimes noted in the fungicidal action of sulfur dusts.

I have shown in my co-pending application, SerialNo. 485,822, filed on even date herewith, that the irregular fungicidal effect observed in sulfur dusts can be overcome if the dusts contain small amounts of an in- 40 organic amphoteric substance when said dusts are applied as fungicides and adhere to the plants.

I have further found that the presence of manganese arsenates in sulfur dusts stabi- 4 lized by said amphoteric substances does in no Application filed October 1, 1980. Serial No. 485,821.

way impair the action of said amphoteric substances and I contemplate in a preferred embodiment of my invention to repare compositions of matter comprising nely divided sulfur, a manganese arsenate and a substance of an amphoteric nature.

From these observations I believe that manganese arsenates are entirely inert as far v cessfully achieved before my invention. The

full beneficial effect of manganese arsenates as insecticides is obtained with compositions of low water soluble AS205. Such insecticides are conveniently prepared by reaction upon a manganese dioxide material with arsenous acid, under steam pressures of about 80 pounds per square inch, and subsequently reacting with an alkaline agent, the arsenate of which is difiicultly soluble in water, upon the manganese arsenates originally formed. Such manganese arsenates contain less than 1% water soluble As O and the man anese arsenates of this type are preferred in my novel compositions of matter.

My noveldusts are mainly intended for the control of cryptogamic diseases on plants. I prefer therefor to prepare my mixtures in such a way that they contain a major amount of sulfur. A composition containing about 90% of finely divided sulfur and about 10% finely ground manganese arsenate of low water soluble AS205 content when dusted on plants gives an excellent control of fungous diseases under ordinary conditions. The proportions of the two ingredients can, of course,

be varied within wide limits, depending upon the particular infections in the field to be treated. Dusts containing increased amounts of manganese arsenate will be beneficial on fields heavily infected with insectswithout loss in the improved fungicidal effect of the sulfur, whereas sulfur dusts containing less than 10% manganese arsenate can be used to advantage when harmful insects are only sparsely present.

My co-pending application cited above discloses that I prefer to stabilize fungicidal sulfur by the admixture thereto of small amounts of substances, such as uncalcined zinc or aluminunioxide, zinc and aluminum hydroxide, basic zinc and aluminum salts, anhydrous zinc and aluminum sulfate, or other zinc and aluminum salts in which zinc and aluminum are the positive ions and which are non-hygroscopic. Only small amounts of said substances, in certain instances, even less than 1%, are required to develop the full insecticidal properties of the sulfur manganese arsenate compositions. 5% of such stabilizing substances have in all instances been found sufiicient, but smaller or larger amounts could be used as well.

To make my novel composition of matter useful as combined insecticides and fungicides, it is necessary that all ingredients be in a finely divided state. Products the ma jority of which passes through a 200 mesh screen, are ordinarily sufficiently divided for my purposes.

My novel compositions are intended to be used as dusts for application in a dry form. This method finds great favor in agriculture over applications of liquid sprays.- It is essential in such dry dusts that the components be in a very. finely divided form and that they do not segregate on storage or during transportation. These conditions are entirely satisfied by my novel compositions. It is furthermore necessary that the dusts adhere, or stick firmly to the plants. In this respect also the addition of non-hygroscopic, finely divided zinc or aluminum compounds to the sulfur manganese arsenate mixtures has proven beneficial, as it improves the adhesiveness of the dusts to the plants.

My novel compositions of matter are particularly intended for use as dusts on fruit trees and flower plants. Excellentcontrol has, for instance, been obtained on black spot, mildew and leaf eating insects on roses. Apple scab and peach leaf curl are likewise easily controlled by application of dusts comprising sulfur and manganese arsenate with or without the presence of amphoteric substances in the dust.

The application of my novel dusts to plants is made in the usual well known manner and ticulturists, they need not be described in detail here. '1

The control of fungi diseases as obtained by the use of my novel dust compositions is illustrated by the following results of various field tests:

Apple scab Total scab infection Material used after treatment in percent 1. Dusting sulfur 300 mesh 23. 9 964 sulfur-manganese ersenate 6. 9 Check, no dusting 98. 6

2. Commercial dusting sulfur 22. 0 90-10 sulfurmangauese arsenate. 17. 5 Check, no dusting 98. 0

3. Commercial dusting sulfur 4. 0 90-10 sulfur-manganese arsenate 1. 1

4. 85-10-5 sulfur manganese arsenate-aluminum hydroxide 38. 9 90-10 sulfur-manganese arsenate 46. 0 Check, no dusting 100.

Peach leaf curl 'ltotal ltlifflclOIl a er Material used treatment 1n percent 85-10-5 sulfur-manganese arsenate-and aluminum sulfate 25-30 85105 sulfur-manganese arsenete and zinc sulfate 15 Check, no dusting 90 This is the first successful control of peach leaf curl known to me as having been obtained with a sulfur dust.

I claim:

1. As a composition of matter a fungicidal and insecticidal dust consisting of sulfur, a manganese arsenate and a substance which under conditions existing when said composition of matter adheres as a dust to plants is of an amphoteric nature.

2. As a composition of matter a fungicidal and insecticidal dust consisting of sulfur, manganese arsenate and a substance selected from the group of substances consisting of the oxides, hydroxides, basic salts and non-hygroscopic salts of metals, the hydroxides of which are of an amphoteric nature.

3. As a composition of matter a fungicidal and insecticidal dust consisting of sulfur, manganese arsenate and a substance selected from the group of substances consisting of the oxides, hydroxides, basic salts and nonhygroscopic salts, in which zinc and aluminum are the anion, of zinc and aluminum.

4. As a composition of matter a fungicidal" and insecticidal dust, consisting of sulfur, manganese arsenate and anhydrous aluminum sulfate.

5. As a composition of matter a fungicidal and insecticidal dust consisting of sulfur, nanganese arsenate and aluminum hydrox- 1' e.

6. As a composition of matter a fungicidal and insecticidal dust consistingh of sulfur, manganese arsenate and a nonygroscopic zinc compound, which under conditions existing when said composition of matter is ap plied to and adheres as a dust to plants, is of an amphoteric nature.

In testimony whereof, I afiix my signature.

HARRY C. YOUNG. 

